package com.zhang.springcloud.lb;

import com.sun.corba.se.impl.oa.poa.AOMEntry;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

@Component
public class MyLB implements LoadBalance{

    private AtomicInteger atomicInteger = new AtomicInteger(0);

    public final int getAndIncrement(){
        int current;
        int next;
        //自旋锁
        do{
           current = this.atomicInteger.get();
           next = current >= 2147483647 ? 0 :current + 1;

        }while (!this.atomicInteger.compareAndSet(current,next));
        System.out.println("******第几次访问，次数next: " +next);
        return next;
    }
    //负载均衡算法：rest接口第几次请求数 % 服务器集群总数量 = 实际调用服务器位置下标 ，每次服务重启后rest接口计数从1开始
    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstances) {

        int index = getAndIncrement() % serviceInstances.size();
        return serviceInstances.get(index);

    }
}
